


Calling My Inner Demons

by One_Purpose



Series: Kuroshitsuji Demons [1]
Category: Kuroshitsuji | Black Butler
Genre: Anal Fingering, Anal Sex, Biting, Demon Ciel Phantomhive, Demon Heats, Demon forms, Dominance, Licking, M/M, Nipple Licking, Rough Oral Sex, Rough Sex, Self-Lubrication, Some BDSM, Submission, handjobs, older Ciel
Language: English
Status: Completed
Published: 2017-06-06
Updated: 2017-06-06
Packaged: 2018-11-09 17:45:36
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 3,612
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11109660
Author URL: https://archiveofourown.org/users/One_Purpose/pseuds/One_Purpose
Summary: It is Ciel's 18th birthday and everyone is over at Phantomhive manor to celebrate. However, something feels...off. He wakes up with sweat covering his body but thinks nothing of it until something happens that only his loyal butler can explain.





	1. Hot and Bothered

**Author's Note:**

> Just thought of this on a whim so...  
> I haven't uploaded in a while and I NEEDED to give you all SOMETHING!  
> Enjoy!

**Summary for the Chapter:**

> It is Ciel's 18th birthday and everyone is over at Phantomhive manor to celebrate. However, something feels...off. He wakes up with sweat covering his body but thinks nothing of it until something happens that only his loyal butler can explain.

**Notes for the Chapter:**

> Just thought of this on a whim so...  
> I haven't uploaded in a while and I NEEDED to give you all SOMETHING!  
> Enjoy!

  The once dark room is shrouded in light as the demon butler whips back the curtains. 

"Good morning, young master. For today's breakfast you will be having imported smoked salmon scrambled eggs, pain perdue with fresh strawberries, bacon quiche Lorraine and a cinnamon bun scone with a fresh glass of Laurent Perrier champagne. I know that champagne isn't exactly the usual Earl Grey you enjoy but it is your birthday after all."

"Don't remind me." Usually he just wakes up, listens to his butler ramble on about his menu and continue on with the rest of his morning routine but he notices a slight interference. For some odd reason, his body is completely covered in sweat even though the temperature in the manor is neither too hot nor too cold. Sebastian seems to notice his body's increased temperature and feels the young master's forehead.

"You're a little warm today, sir. Shall I postpone the party for next week?"

"None of that, Sebastian. I'll be quite fine after I've had my bath." Though reluctant, he bows and replies,

"Of course. You're bath is ready for you."

 

  Sebastian begins to follow his master into the bathroom but is halted in the doorway.

"Sir?"

"I..I think I'll do this by myself today. You just go and make any last minute preparations. I am an adult after all, I can't have you doing every simple task for me."

"Very well. I'll make sure the others haven't broken anything. Your clothes have already been laid out, I understand if you want to do that yourself also."

"Good. Thank you, Sebastian." With that, the butler leaves and heads down the hall towards the garden where he sees Baldroy, Finnian, and Mey-Rin laughing amongst each other while Tanaka is silently drinking his tea.

"Good morning everyone." He approaches with a 'smile'.

"GOOD MORNING SEBASTIAN!" They all shout in unison. 

"Where's the birthday man?" Baldroy puts his hands on his hips.

"He will be out shortly. Now, there's been a minor situation with young master."

"Oh, what's wrong?" Finnian looks genuinely concerned.

"It seems as if he has a fever this morning so I want you all to keep a keen eye on him. If he begins to act strangely  and I'm not there to see it, come find me quickly."

"It sounds like you know what's happening to him." Mey-Rin adjusts her cracked glasses on her face.

"Yes, possibly but I can't be sure just yet. I must go see if the young lord is ready." He turns to leave but stops momentarily to add, "Oh, and make sure not break anything. This is a very important day for the master and nothing, _absolutely nothing_ , can go wrong. Is that clear?" The butler gives them his signature 'smile' and they all quiver, except for Tanaka of course.

"Y-YES SIR!"

 

Entering Ciel's quarters, Sebastian sees him slumped on the bed with his shirt unbuttoned and his hands in his midnight blue hair. Sebastian walks over to finish dressing the young man while examining his face.

"I'm not trying to pester you, sir, but I think you should be resting at this time."

"Nonsense! I'm perfectly fine and perfectectly capable of attending my own party without keeling over."

"Well, I certainly hope so. The mess would unbearable to clean up." Ciel rolls his eyes and finishes slipping on his shoes before heading down to the dining table to eat. He has to admit, the champagne is a good touch seeing as he hasn't had it in a while. He prefers not to drink it much because getting drunk won't get any work done. And he is a busy man. A nice treat is acceptable every now and again, like a reward for all the hard work. 

"How big is this party anyways?" 

"Not as big as the business parties we often have. Actually, it's going to be quite small. I already know that celebrating birthdays isn't your favorite so I've only invited a handful of people we know."

"Well, that's a relief." The young master wipes his forehead, a pink ting to his cheeks. Sebastian's stomach does something weird when he sees his young lord stare up at him with that expression. They stay like that for a moment, silently eye-locked with each other, drinking in each other's company until Pluto comes bursting through the door with Finnian, Baldroy, and Mey-Rin chasing after him.

"We're sorry master Ciel! He saw a squirrel and started going crazy!" However, Ciel doesn't say anything and only stands from his seat and walks out of the room leaving everyone else in a deep state of confusion.

~~~AT THE PARTY~~~

  Everyone is gathered in the back yard, several tables full of fine meats and desserts along with refreshing beverages. Grell is currently attatched to Sebastian's arm while William is attempting to pull him off. Ciel is taking refuge in the shade to calm his heated skin.

"Ciel!" Elizabeth comes running over, her famous pink dress fitted tightly to her body. Now that she's older, her body has more curves and she has become quite busty. Of course, Ciel has always believed that she is attractive, and he would often keep the whole future husband and wife charade into play but lately it's getting old. He doesn't want to marry Elizabeth because he just doesn't feel that way towards her. Sure, he used to have some feelings for her when they were younger but now it would be childish to continue playing house when it's pointless nowadays.

"Hello, Lizzy." 

"Oh my, you look awful. Are you sick?"

"I'm fine. It's just hot today."

"I think it's quite nice out today...wait,"

"What?" She gets closer to him, a smirk on her face as she bites her lip. 

 

  "I understand what's going on."She puts her hands on his chest and slides them down to the waist of his pants, her thumb slipping just under the button, way too close to the place that's causing all this. "I can take care of it. Let's go to your room, no one will even know we're gone."

"Stop it, Lizzy."

"You don't have to act all serious, my dear husband. Let your future wife take care of this for you. I can make you feel so good, and I know you can make me feel good too."

"Disgusting." She pauses, her eyes going wide as she stares at him. 

"Excuse me?" 

"You heard me. You're disgusting. I am not your husband, nor will I ever be. This childhood romance we once had is over now. I've moved on, my feelings have change. And so should yours."

"But we HAVE TO get married. You don't know what you're saying!"

"You're making a scene."

"I don't care! Why don't you love me!"

"I already told you. My feelings have changed. If you continue to disrupt my party then I'll have to ask you to leave." She turns and runs without saying another word, all eyes are on the scene happening in front of them. "Everyone get stack to the party! There's nothing to see here." They follow orders but can't  help but wonder what just happened.

 

  Ciel finds his way behind one of the trimmed trees and leans against it. His fever has only increased by the minute and he feels as if he could collapse. 

"My lord." He looks up to see his butler standing over him. Even though he has hit a growth spurt and grew many more feet, a little taller than Finnian, Sebastian still seems to tower over him.

"Sebast.." He feels the man lift him up into his arms like he use to when Ciel was a child and starts carrying him inside.

"Is everything okay, Sebastian?" Grell asks. "Is little Ciel sick?" Ciel doesn't have the energy to get angry at the comment.

"No, it appears as if he has twisted his ankle so I am going to ice it. He'll be back out shortly." Mey-Rin offers to help but Sebastian insists that he goes alone. He gets to Ciel's room with lightening speed and lays him on the bed.

"What the hell is going on? Am I honestly sick?" Ciel clutches his stomach.

"Not quite."

"Well then whAAAAAAAAAAaaaaaaah!" A loud moan escapes him as he flops back onto the bed. Another wave assaults him and his back arches painfully. The aroma is absolutely intoxicating to the butler's nostrils, he can already feel himself changing. When he looks at his young master he sees the grey horns beginning to sprout from his head and a long marine blue tail flap around on the bed. "Aahah-aaaaaaah!" 

"My lord.." His own horns start to sprout as well as his own tail, both much larger than Ciel's. "Don't be afraid. What your going through is called a heat."

"L-Like a mere a-ahhhh-animal?"

"Like a demon. These only happen every few thousand years but since you are new to this, your heats will be much more frequent. I can help you through this, sir. But I'll need your permission before I do so." Ciel says nothing and writhes in pain. He wants to beg for his butler to ease his pain but he is the head Phantomhive. He doesn't beg... he can't beg. Nothing happened since for a few moments except the constant whimpering moans of the the heated young man. "Sir, this isn't easy but I promise you, if you don't let this happen, you'll suffer more pain than you are currently in." 

 

  This seems to sway Ciel into agreeing but he is still unsure. Sebastian starts to undress his master first, stripping him down to nothing before unclothing himself. Ciel's skin is flushed and feels like boiling hot metal. Sebastian's hands wander over broad shoulders and a toned chest before stopping at the perky pink nipples ready to be teased. 

"Submit to me." Sebastian whispers hotly into the young man's ear. The blue demon whimpers fighting back the sinful urges trying to erupt from him. "Look at you, my lord. You're body is so hot and you smell absolutely Devine. I want to eat every inch of you." He nips at Ciel's ear, moving down toward his shoulder. Ciel whines hotly as a hand reaches up to grab at raven hair. "When we are done here, the only thing you'll know, is my name and my scent. When we are done here, you're body belongs to me and only only me."

"Mmmh! Y-yes-s... Sebast-ain."

"That's right, say my name."

"Se-Sebastian."

"Mmmmmm.. again, louder."

"Sebastian!"

"LOUDER!"

"SEBASTIAN!" The butler roughly grabs onto pale shoulders and pushing  the other forward so they are lying on their stomach with spread legs. He gets between those plush cheeks that taunt him from a distance and spreads them open with his hands. There is a clear liquid already leaking out of that puckered hole like honey, so taunting... He leans his head down and goes to town licking and sucking, trying to drink up as much of those juices as he can.

"Aahah-aaaaaaah! Oooh YEES!" Looks back at the scene of his butler's well-framed face buried between his cheeks. Ciel pulls himself away with as much strength as he can summon and gets face to face with the larger man's erections. It has a nice girth and a very satisfying length, Ciel can practically hear his body singing for that to be inside of him. 

"It's s-so..." His voice trails off as he sucks it into his mouth with a satisfied hum, Sebastian growls loudly and thrusts up into that hot mouth. The other doesn't seem to mind though. In fact, he is squeezing Sebastian's thighs asking for more. So that's what he is given.

 

  Sebastian roughly thrusts up into the mouth and he feels the tip of his cock hit the back of his young lord's throat. He grabs onto Ciel's head to keep it steady, his thrusts become more shallow and fast pace.

"Grrrrrrrggghh! Rrrrrggh!"

"MM MMMH!" Those big blue eyes close as tears escape them and he feels the hot semen spill down his throat. They don't rest for a moment. As soon as Sebastian finishes, he pulls Ciel up and attacks his lips, biting them with his pointy fangs.

"I hope you're ready, my lord... Because things are about to get much more intense."


	2. Let's Get This Party Started

**Summary for the Chapter:**

> Fun ;)

**Notes for the Chapter:**

> Well, I mean...what can I say?

  The party is long forgotten as claws rip and teeth sink into hot flesh. This has to be the only time Ciel has felt his butler's body so warm in all the years he's known him. He's not complaining though, quite the opposite. He loves feeling Sebastian's hard body over his, dominating him with everything he has. Those polished finger nails rake down the young lord's thigh earning him a bark of a whine. 

"Sebastian, stop this teasing at once!" An echoing smack rings throughout the room, a bright red hand mark is printed onto Ciel's thigh. The sting is unbearable but oh so good.

"Oh? Did you say something, my lord?" Ciel's lips are sealed tight but the immense pleasure wracking his face is enough of an explanation. He roughly flips the younger onto his stomach and pulls him into his bare lap. 

"W-WHAT ARE YOU DOING!? STOP - AAAAAAAAAAAAAAAAHHHHH!!" **Smack!** Ciel's back arches as another slap lands on his skin, this time his cheeks are feeling the assault. _What hell am I doing? I am Ciel Phantomhive, the head of the Phantomhive estate! I sh-shouldn't be...but I can't help it. My body hurts so much and Sebastian..oh Sebastian..._

"That's just not going to do. I wanted to make you speechless but not silent. No matter, I know just how to fix that." **Smack! Smack! Smack!**

"Sebaaaahhh!"

 

  The tension mixed with the his young master's scent is too much. He can feel himself getting harder and harder with each each passing moment. Ciel flops back onto his back but tries to keep his bruised bottom off of the blankets. The blue demon's eyes are blown with nothing but lust. 

"Ciel..." The butler reaches down somewhere under the bed and pulls up some black leather cuffs his master's wrists to the headboard. The other doesn't look upset at all, he is very obviously enjoying this if the way he is whining and writhing around is any clue. He then drives those legs up so they are bent at the knees and positions himself at the entrance. "This may hurt." His expression isn't sympathetic seeing as that smirk hasn't left his face.

"Just do it. I want to feel you slide inside, stretching me with that big cock." Sebastian groans as he twitches at the statement, and slides inside of that tight heat feeling the walls squeeze but stretch so nicely for him. He had a feeling that this would happen to Ciel when he started showing signs on his sixteenth birthday. Whenever Ciel would make a decision that was bound to end badly and Sebastian would scold him for it, Ciel would hold his head down and tilt it to the side. To anyone else this would be unnoticeable but Sebastian is not anyone else and has seen everything. 

 

  The thrusts start off slow and controlled since this is master Ciel's first heat but he is forced to speed up when pale hips grind up to meet his thrusts. 

"I'm trying to go easy on you, sir."

" _D-Don't_... please don't. I want to feel you stretch me.. Mmm!" Sebastian picks up the pace, leaning down with his hands on the master's shoulders to use as leverage. And as if on cue, fangs sink into the skin between his neck and shoulder, stilling his thrusts as a wave of hot lava spreads through his veins and he begins to pound into the one below him sending the other into a fit of moans. "O-oh-ooo!!" His hips become erratic as he pounds into the young demon below him, relentlessly searching for that spot that will help Ciel reach nirvana. He angles his hips and lifts the other's up just a little until finally,

"SEBASTIAN! SEBASTIAN THERE, PLEASE!"

"Ugh, m-my lord. You're squeezing me so much. You must really be feeling it."

"UH-Uncuff my hands. I need to grab onto something." 

 

  Feeling a bit of mercy, he uncuffs Ciel's hands only to be pushed back, his dick slipping out with a pop. Sebastian isn't very happy with this, not at all. If Ciel thinks he can just walk away and leave him like this, he's certainly mistaken. However, that isn't what happens: Ciel flips himself over and raises his ass as high as he can with his chest pressed against the bed. His butt is turning purple from the spanking but he doesn't seem to mind. Sebastian isn't faring to we'll on his end; his skin is simply crawling with pleasure at the sight of this young demon presenting himself to him so willingly. He just itching to touch that skin, bruise it some more. He decides to lean down and take one of those firm cheeks in his mouth and give it a good bit. The taste and feel of the blood sliding down his throat is like wine, rich and always leaves you wanting more. Ciel practically howls, urging the butler on even more, but this time he moves just below the other cheek and bites down. 

"No more...oh god..."

"I can't hear you, Ciel. You'll have to speak up."

"Please, just.. fuck me."

"I said _speak up._ " 

"Fuck me! Fuck me! Fuck me!"

"You want me back inside you?"

"Yes!"

"You want me to fill you up with my seed while you lay there and cum all over the clean sheets?"

"Yes, yes! I just want you to fuck me! Hard, fast, deep! I want it!"

"Mmmmmm, as you wish. " He sinks back into Ciel's tight heat and immediately starts a hard, fast pace. He loves it, Ciel loves it, they both love it. They crave the contact right now and neither of them wants it to stop. 

 

"Aaaaaaahhhh!! Yeees, fuuuck! Harder! I want to be able to feel it tomorrow!"

"Oh you'll feel it. I'll fuck you so hard it will feel like I'm still inside you when this is over." He hits Ciel's spot over and over, ripping scream after scream out of him. He has managed to reach his hands back from the position he is in and dig his nails into Sebastian's arms. 

"I'm g-g-gonna cum! AAH I'M GOING TO CUM!" Sebastian's eyes clench shut and his thrusts never slow down, in fact, they speed up.

"I am too. O-oh, don't tense yourself like that, Ciel. Don't...a-uh." Ciel's hips rock back into Sebastian's, their skin slapping together loudly in the room.

"I'M CUMMING! SEBASTIAN, CUM IN ME! GIVE ME EVERYTHING YOU'VE GOT! FILL ME UP WITH YOUR BABIES!" And that's it. Like a bomb, his body jerks as he releases inside the young demon, filling him to the brim. Ciel howls once more and spurts all over the blankets as his body arches and muscles tense. It takes a long moment for their bodies to calm down but eventually they collapse onto the bed, Ciel on his stomach and Sebastian on his back beside him.

"We should get cleaned up. The guests are waiting for you."

"I'm not exactly in the position to move, Sebastian."

"I'm aware. Which is why I am going to carry you. We'll have a quick bath and change our clothes before we head back.

~~~BACK AT THE PARTY~~~ 

  They walk back side by side as if nothing had happened, their demon forms have turned back to their original forms but when they get down the hall they see all of the guests inside staring at them. William is the one to break the silence and approaches the two with his natural stoic face.

"It started to rain so we had to bring the party inside. Didn't we?" He looks back at the servants.

"Y-Yeah, but we couldn't save everything."Baldroy says.

"A-all the drinks spilled when we tried to run them inside." Mey-Rin shakily smiles.

"Yeah and plus th-they wouldn't have been good with all the rain water in them." Finnian adds. 

"Well alright. I'll go fetch some more drinks then. You all go back to enjoying the party." Everyone turns back to each other to mingle but William grabs Sebastian's sleeve before he can leave and looks at him with a deadly expression.

"Next time you two want to frolic with each other, try being a bit more quieter."

"We weren't aware that everyone would be coming inside in the first place so don't try to lecture me."

"I'm sure you knew you'd be coming inside though." And he walks away. Ciel's is in a permanent state of tomato as he glares up at his butler.

"Everyone heard us!?" He yells whispers.

"Everyone heard _you_. Don't be so embarrassed, my lord. You're an adult now so there's nothing to worry about. I'm just glad this happened on your eighteenth birthday and not sooner."

"You knew this would happen!?"

"Not quite but I saw the symptoms. I would have told you if I was absolutely sure."

"Whatever. Just go get the damn drinks."

"Yes, my lord. Oh, one more thing."

"What?"

"It could happen."

"What the devil are you talking about?"

"'What you said about filling you up with my babies. You're a demon so... it's possible..."

"WHAT THE HE- Am I pregnant!?"

"There's always a chance." Sebastian leaves Ciel standing there full of anger and confusion. Despite all that's happened, he has to admit, this may have been his favorite birthday.


End file.
